This application claims the priority of German Application No. 199 06 416.4, filed Feb. 16, 1999, the disclosure of which is expressly incorporated by reference herein.
The invention refers to a torque adaptation device for an engine moment model and, more particularly, to a device for torque adaptation, at which at least one computation unit is provided, which determines an engine moment with the help of an engine moment model from performance characteristics and/or sensor input parameters, such as engine temperature, load, or engine speed.
Engine moment models for the determination of engine moments are generally known and used in engine, transmission and chassis control units. Conventional engine moment models calculate the engine moment from inputs of performance characteristics and sensors, such as engine temperature, load and/or engine rpm.
However, what is not factored into previous models, especially as a sensor input parameter, is the output moment that exists in the drive train following a clutch disengagement.
Through a purely mathematical model computation of the engine moment it is possible that this computated engine moment may deviate from the actual engine moment by up to 20% with standard engines, due to power tolerances. However, since the engine moments in the individual transmission control units are used as input parameters for adjustment or control operations, it thus naturally also results in making the respective engine, transmission and chassis adjustments or controls inaccurate.
It is thus the object of the present invention to describe a device for torque adaptation for an engine moment model with which the engine moment can be determined accurately.
This goal is achieved by a device for torque adaptation, at which at least one computation unit is provided, which determines an engine moment with the help of an engine moment model from performance characteristics and/or sensor input parameters, such as engine temperature, load, or engine speed. This invention is characterized in that a sensor is provided to capture a moment which exists in a transmission output shaft between a clutch of the internal combustion engine and the driven wheels. The sensor generates a signal that corresponds to the moment for at least one computation unit. The computation value is developed in such a way that the engine moment which has been determined from the model can be corrected as a function of the acquired moment.
In particular, a sensor is used to determine the moment that exists in a drive shaft between a clutch and the driven wheels. The sensor is preferably mounted on the actual transmission output or cardan shaft, and it transmits the engine moment that occurs on this shaft in a contactless manner.
A signal from the sensor proportional to the captured drive moment is sent to a control unit and serves to adapt the engine moment that has been determined from the model.
The accuracy of the engine moment can be significantly increased with the aforementioned adaptation, so that deviations of only up 2% occur in static operation, and up to 5% in transient operation.
The accuracy of the determined engine moment, and thus the accuracy of the control units operated thereby is improved overall, for example, the shifting accuracy in automatic transmissions (also in semiautomatic transmissions) and the control accuracy of chassis devices, especially as they occur during a sudden brake application. As a result, vehicle safety can be improved as well. In addition, an accurate engine moment will also be of great advantage in future engine concepts, as for example in a variable valve drive or a direct fuel-injected engine.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.